Hi There, About 8 Years Ago I Experienced Passing Blood

Hi there, about 8 years ago I experienced passing blood clots after sex, I sought medical help and was told to drink copious amounts of water which seemed to help me flush my kidney. A number of medical test were carried out, and no cancerous or worrying causes were found and was given a full bill of health. I have had periods of celibacy but find on occasions during ejaculation after sex or masturbation, there is clotting and blood .This is not a regular occurrence, just irregular